Isolation and characterization of isomeric tibetin spiroethers from the roots of Tanacetum dolichophyllum (Kitam.) Kitam.

The roots of Tanacetum dolichophyllum (Kitam.) Kitam. (syn. Hippolytia dolichophylla (Kitam.) K.Bremer & Humphries) were collected from high altitude area of Munsyari, district Pithoragarh (Uttarakhand, India) yielded essential oil by steam distillation method and the oil was analysed by TLC and GC-MS. The GC-MS analysis of the essential oil sample showed the dominance of two constituents visible in sesquiterpene range. These constituents were isolated by column chromatography. The structures of these compounds were determined on the basis of 1H-NMR,13C NMR, COSY, 135-DEPT, and HRMS (ESI-TOF) spectral data. The two major compounds were identified as isomeric C14-Tibetin spiroethers, namely (E)-2-(2',4'-heptadiyn-1'-ylidene)-1,6-dioxaspiro[4.4]non-3-ene and (Z)-2-(2',4'-heptadiyn-1'-ylidene)-1,6-dioxaspiro[4.4]non-3-ene.

A comparative study on chemical composition and antibacterial activity of essential oils from the aerial parts and roots of Laportea bulbifera (Siebold & Zucc.) Wedd. growing in the Central Himalayan region.

The GC and GC/MS analysis of the essential oil samples obtained separately from whole aerial parts and the roots of Laportea bulbifera resulted in the identification of a total of 40 compounds from the whole aerial parts and 45 compounds from the roots representing 89.7% and 82.9%, respectively, of the total essential oil composition. The essential oil from aerial parts is dominated by oxygenated sesquiterpenes (66.4%) with α-elemol (55.1%), germacrene D-4-ol (4.2%), linalool (3.5%) and phytol (3.4%) as the major constituents while the root essential oil is dominated by oxygenated monoterpenes (30.4%) with trans-myrtanol (16.3%), cis-myrtanol (11.6%), nopinone (7.8%), cadin-4-en-10-ol (4.7%), and α-elemol (3.4%) as major constituents. The essential oil from whole aerial parts showed bactericidal effect at 250 µL/mL concentration (MBC) against Pasteurella multocida and Dickeya dadantii while the root essential oil exhibited bactericidal effect at 125 µL/mL against Escherichia coli, Enterococcus faecalis, Xanthomonas phaseoli, and Dickeya dadantii.

Polymer grafted magnetic graphene oxide as a potential nanocarrier for pH-responsive delivery of sparingly soluble quercetin against breast cancer cells.

In this work, polymer grafted magnetic graphene oxide (GO-PVP-Fe3O4) was successfully synthesized for efficient delivery of anticancer drug. Firstly, GO was functionalized with the hydrophilic and biocompatible polymer polyvinylpyrrolidone (PVP) and then grafted with magnetic nanoparticles (Fe3O4) through an easy and effective chemical co-precipitation method. Quercetin (QSR) as an anticancer drug was loaded onto the surface of GO-PVP-Fe3O4 via non-covalent interactions. The drug loading capacity was as high as 1.69 mg mg-1 and the synthesized magnetic nanocarrier shows pH-responsive controlled release of QSR. The cellular cytotoxicity of the synthesized nanocarrier with and without drugs was investigated in human breast cancer MDA MB 231 cells and their effects compared on non-tumorigenic epithelial HEK 293T cells. These results reveal that the drug loaded GO-PVP-Fe3O4 nanohybrid was found to be more toxic than the free drug towards MDA MB 231 cells and exhibits biocompatibility towards HEK 293T cells. Overall, a smart drug delivery system including polymer grafted magnetic graphene oxide as a pH-responsive potential nanocarrier could be beneficial for targeted drug delivery, controlled by an external magnetic field as an advancement in chemotherapy against cancer.

Bulk synthesis of graphene nanosheets from plastic waste: An invincible method of solid waste management for better tomorrow.

Waste plastic management and converting it into value added products is one of the greatest challenges before the scientific community. The present work reports a cost effective, environment friendly and mass production capable method for upcycling of solid plastic waste into value added product (graphene). A two step pyrolysis processes i.e. firstly at 400 °C in presence of nanoclay followed by at 750 °C under nitrogen atmosphere was performed to obtain a black charged residue. Raman spectroscopy was performed on the obtained residue, where the observed D and G bands at 1342 cm-1 and 1594 cm-1, respectively, confirm the synthesis of graphene nano sheets. In addition, a broad 2D band at 2790 cm-1 confirm the presence of few layer graphene nano sheets. The obtained graphene nanosheets were also confirmed through the computational data by Gaussian09, where the peaks at 1379 cm-1 and 1596 cm-1 for D and G band, respectively, make a good agreement with experimental data. TEM, FT-IR and EDX spectroscopy were also performed to confirm the synthesis of graphene nanosheets including the functional group identification and quantitative analysis for elements, respectively.

Terpenoid composition of essential oil from a new chemotype of Selinum wallichianum Raizada & Saxena.

Essential oil samples obtained by steam distillation of the whole aerial parts and roots of Selinum wallichianum Raizada & Saxena (syn Selinum tenuifolium) growing wild in the Himalayan region of Uttarakhand, India, were analysed by capillary gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). A total of 24 and 43 constituents representing 97.0 and 95.4% of the oil composition, respectively, were identified. Both the oil samples were constituted mainly of monoterpene hydrocarbons 68.1 and 77.4%, with sabinene 31.0 and 11.5%, ß-phellandrene 18.2 and 34.5%, α-bisabolol 16.0 and 1.8% and α-phellandrene 3.5 and 11.2%, respectively, as a major constituents. Presence of sabinene, ß-phellandrene, α-phellandrene and complete absence of previously reported 3,5-nonadiyne (53.8-90.0%) justifies it to be a new chemotype of S. wallichianum.

Composition and antibacterial activity of essential oil from Scutellaria grossa Wall ex Benth.

The chemical composition of the steam volatile oil of the whole aerial part of Scutellaria grossa Wall ex Benth. (Lamiaceae), obtained by steam distillation, has been analysed by capillary GC and GC-MS. The oil was found to be rich in oxygenated monoterpenes (88.6%). A total of 50 constituents were identified, representing 94.4% of the total oil composition. Linalool (37.0%) and 1-octen-3-ol (32.0%) were found to be the principal constituents. The antibacterial activity of the oil was determined against 10 bacterial strains by measuring the growth inhibitory zones. The oil showed significant antibacterial activity against Gram-positive bacteria, Bacillus subtilis and Enterococcus faecalis, and the Gram-negative, Klebsiella pneumoniae and Salmonella enterica enterica. A minimum inhibitory concentration of 31.25 µL mL(-1) was observed against E. faecalis.

Chemical composition and antibacterial activity of essential oil from Salvia mukerjeei.

The composition of steam volatile oil from aerial parts of Salvia mukerjeei Bennet & Raizada (Lamiaceae) was analyzed by capillary GC and GC-MS. The oil was rich in sesquiterpene hydrocarbons (67.3%). Among 71 identified constituents representing 91.7% of the oil, beta-caryophyllene (28.7%), gamma-muurolene (15.5%) and dehydro-aromadendrane (9.5%), were the principal constituents. The oil was tested against ten bacterial strains and was active against Enterococcus faecalis, Erwinia chrysanthemi and Agrobacterium tumefaciens.

Terpenoid composition of the essential oils of Teucrium royleanum and T. quadrifarium.

Teucrium royleanum Wall ex. Benth. and T. quadrifarium Buch.-Ham., growing wild in the Central Himalayan region of Uttarakhand (India), yielded, on steam distillation, 0.07% and 0.09%, respectively of essential oil. The oil samples were analyzed by GC and GC-MS. By GC, both oil samples showed remarkable similarity with respect to the major peaks. Fifty-seven constituents were identified in both the oils representing 96.0% and 96.6% of the total, respectively. The oils were rich in sesquiterpene hydrocarbons (approximately 76.0%). beta-Caryophyllene (23.6% and 38.3%), germacrene D (28.9% and 9.4%), alpha-humulene (5.7% and 5.9%), linalool (4.8% and 1.5%), and 1-octen-3-ol (8.5% and 0.7%) were common to both oils and were the principal constituents. The genus can be classified into two groups on the basis of the present and previous reports on the essential oil composition and chemical markers.